System.Process readProcess incorrect documentation of return value

[benc]

The System.Process docs here:

http://haskell.org/ghc/docs/6.12.2/html/libraries/process-1.0.1.2/System-Process.html#v%3AreadProcess

describes the return value as:

returns either the output string, or, in the case of non-zero exit status, an error code, and any output.

and the given example output is:

Right "Thu Feb 7 10:03:39 PST 2008\n"

This suggests that the return value looks like: IO (Either ? String)

But the return type is shown (in that same documentation, and in ghci 6.12.3) as IO String, and my own experimentation shows no "Right" being returned in the case of a successful operation - instead I get only the String containing the program output, not wrapped.

Perhaps this is historic.

[refold]

I forwarded this to the GHC devs.